Composite rim of vehicle wheel and method of manufacturing the same

ABSTRACT

Disclosed are a composite rim of a vehicle wheel and a method of manufacturing the same, which is reduced in weight through the use of a continuous fiber composite. The rim of a vehicle wheel may be formed by stacking composite sheets, each prepared by impregnating fibers with a resin to form a sheet. The composite sheets may be stacked in multiple layers such that end portions of the respective composite sheets may contact each other in a circumferential direction of the wheel, and discontinuous interfaces, formed at the contacting end portions of the respective composite sheets along an axial direction of the wheel, may not be aligned with each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Korean PatentApplication No. 10-2018-0059377, filed on May 25, 2018 in the KoreanIntellectual Property Office, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a rim of a vehicle wheel and a methodof manufacturing the same by using composite sheets comprising a fabricsheet and a resin to reduce weight of the rim.

BACKGROUND OF THE INVENTION

Generally, a driving wheel for a vehicle is an assembly of a wheel and atire, and serves to support the weight of a vehicle, to transfer force,such as driving force and braking force, and to alleviate impactstransferred from the road surface.

For instance, the wheel serves as a support structure of the drivingwheel, and therefore has been formed of steel or aluminum having goodmechanical properties.

In recent years, as the demand for reduction in the weight of vehicleshas continued, research into a wheel formed of a fiber-reinforcedcomposite has been conducted with the goal of reducing the weight of awheel formed of a metal. For instance, a spoke and a rim, whichconstitute the wheel, have been formed of a fiber-reinforced compositeand a hybrid type in which a spoke is formed of a metal, such as steelor aluminum, and only a rim has been formed of a fiber-reinforcedcomposite and is then coupled to the spoke.

FIG. 1 is a view illustrating a general hybrid-type wheel. Asillustrated in FIG. 1, in the hybrid-type wheel 10, a spoke 20 formed ofa metal and a rim 30 formed of a fiber-reinforced composite aremanufactured separately, and thereafter the spoke 20 and the rim 30 aremechanically coupled to each other using a fastening member such as abolt. The rim is formed of a fiber-reinforced composite, which isreinforced with high-rigidity and high-strength fibers, such as carbonfibers, glass fibers, or aramid fibers.

The fiber-reinforced composite, used in the rim, may be broadly dividedinto a discontinuous fiber-reinforced composite, a continuousfiber-reinforced composite, or a discontinuous/continuous fiber mixedreinforced composite. In the case of the discontinuous fiber-reinforcedcomposite, the rim may be molded by compression molding or thermoplasticinjection molding using a sheet molding compound (SMC).

In the case of the continuous fiber-reinforced composite, the rim may bemolded by stacking prepreg and performing compression molding thereon,or by stacking layers of fabric and performing resin transfer molding(RTM) thereon. In addition, the rim may be molded by winding continuousfibers and impregnating the same with a resin.

The discontinuous fiber-reinforced composite may have low mechanicalstrength and rigidity, and therefore is disadvantageous from the aspectof reducing the weight of a wheel compared to the continuousfiber-reinforced composite in terms of required wheel performance.

For this reason, in the related arts, the continuous fiber-reinforcedcomposite can be applied to reduce weight, as well as satisfying highmechanical strength and high rigidity. However, in the case in which therim is molded using the continuous fiber-reinforced composite, thegeneration rate of defects, such as wrinkles, may be increased duringcontinuous winding. Moreover, when the rim is molded by stacking layersof discontinuous fabric, problems such as difficulty in processing a cutsection may continue to occur.

SUMMARY OF THE INVENTION

In preferred aspects, the present invention may provide a composite rimof a vehicle wheel and a method of manufacturing the same. The compositemay solve the above-described problem, for example difficulty inprocessing a cut section, while satisfying all of reduced weight, highmechanical strength, and high rigidity. The composite may include acontinuous fiber-reinforced composite.

In one aspect, provided is a rim of a vehicle wheel. The rim may beformed by stacking a plurality composite sheets, each prepared byimpregnating continuous fibers with a resin to form a sheet.

The fibers may be, for example, naturally provided or syntheticallyproduced substance or material that may have much greater length in onedimension by at least 10 times, at least 20 times, at least 50 times, atleast 100 times, at least 200 times, at least 300 times, at least 400times, or at least 500 times than a width or diameter thereof. Thefibers may suitably provide properties related to the length direction,e.g., strength applied along the length direction of the fibers.

The resin may be, for example, a liquid, or semi-solid material that maybe naturally provided or synthetically produced, and the resins may beconvertible into polymers by suitably curing process, e.g., UV curingand thermal curing. The resin as used herein may suitably includesynthetic resins including one or more kinds of curable monomers, whichmay be polymerized upon irradiation of UV or applying heat.

Each of the plurality of the composite sheets suitably may be the sameor different as one or more other composite sheets. A plurality ofcomposite sheets may suitably contain at least about 3 sheets, 5 sheets,10 sheets, 15 sheets, 20 sheets, 25 sheets, 30 sheets, 40 sheets, 50sheets, 60 sheets, 70 sheets, 80 sheets, 90 sheets, or 100 sheets.

The rim of a vehicle wheel may include a plurality of composite sheetsand each of which may include a fabric sheet and a resin. Preferably,the resin may be impregnated in the fabric sheet. Preferably, thecomposite sheets may be stacked in multiple layers and the end portionsof the respective composite sheets may contact each other in acircumferential direction of the wheel. Preferably, discontinuousinterfaces of the respective composite sheets may be formed at thecontacting the end portions of the respective composite sheets along anaxial direction of the wheel and may not be aligned with each other.

The term “discontinuous interface” as used herein refers to an interfacebetween at least two end portions of a single composite sheet(respective composite sheets), which is covering or surrounding an outersurface of a rim of a vehicle such that two end portions contacts toeach other. The discontinuous interface may be formed at a portionconnecting a first side of the single composite sheet and the secondside of that single composite sheet.

Preferably, each of the fabric sheet may include continuous fibers.

The term “continuous fibers” as used herein refers to a bundle includinglong, continuous strand of fibers such that a length there is at leastgreater by about 100 times, 200 times, 300 times, 400 times or 500 timesor more greater than the width of the diameter thereof. The continuousfibers may suitably be produced using synthetic materials, e.g., frompetrochemicals or polymerizations.

The rim may include a base layer comprising one or more of the compositesheets wherein the end portions of the respective composite sheets inthe base layer contact each other in the circumferential direction ofthe wheel and the discontinuous interfaces of the respective compositesheets in the base layer are formed at the contacting end portions ofthe respective composite sheets in the base layer in the axial directionof the wheel, and a reinforcement layer disposed on the base layer andcomprising one or more of the composite sheets wherein the end portionsof the respective composite sheets in the reinforcement layer contacteach other in the circumferential direction of the wheel and thediscontinuous interfaces of the respective composite sheets in thereinforcement layer are formed at the contacting end portions of therespective composite sheets in the reinforcement layer in the axialdirection of the wheel. Preferably, the discontinuous interfaces formedin the base layer and the discontinuous interfaces formed in thereinforcement layer may not be aligned with each other.

The reinforcement layer may be formed in multiple layers by stacking theone or more composite sheets. The discontinuous interfaces of therespective composite sheets in the reinforcement layer may be formed atthe contacting end portions of the respective composite sheets in thereinforcement layer in the axial direction of the wheel and thediscontinuous interfaces of the respective composite sheets in thereinforcement layer may not aligned with each other.

The rim may include a rim body having a cylindrical shape, a rim outerportion, and a rim inner portion. The rim outer portion, and a rim innerportion may be formed both axial ends of the rim body so as to have anincreased diameter. Each of the composite sheet may include a body areaforming the rim body, an outer area forming the rim outer portion, andan inner area forming the rim inner portion. Preferably, the outer areaand the inner area of the composite sheet may include cutting portions,which are cut in the axial direction of the wheel and are spaced apartfrom each other in the circumferential direction of the wheel.

The cutting portions may be spaced apart from each other by a length ofan arc corresponding to an angle about a center of the rim, and theangle may be equal to or less than about 5 degrees.

Preferably, a heat-resistant resin may be impregnated in the body areaof the one or more composite sheets constituting the base layer, animpact-resistant resin may be impregnated in the outer area and theinner area of the one or more composite sheets constituting the baselayer, and a fatigue-resistant resin is impregnated in the one or moreof the composite sheets constituting the reinforcement layer.

Further provided is a vehicle including the rim as described herein.

In another aspect of the present invention, provided is a method ofmanufacturing a rim of a vehicle wheel. The method may include preparinga mold corresponding to a shape of the rim, preparing a plurality offabric sheets, stacking the respective fabric sheets in multiple layerson the prepared mold, and injecting and curing a resin into the stackedcontinuous fiber fabric sheets. Preferably, end proportions of therespective fabric sheets may contact each other in a circumferentialdirection of the mold. The discontinuous interfaces of the respectivefiber fabric sheets may be formed at the contacting end portions of therespective fabric sheets along an axial direction of the mold and maynot be aligned with each other.

Each of the fabric sheet may include continuous fibers and the fabricsheet may be prepared by weaving continuous fibers.

The stacking may include forming a pre-base layer by disposing one ormore the respective fabric sheets on the prepared mold such that the endportions of the respective fabric sheets may contact each other in thecircumferential direction of the mold and the discontinuous interfacesof the respective fiber sheets in the pre-base layer may be formed atthe contacting end portions of the respective fabric sheets in the axialdirection of the mold, and forming a pre-reinforcement layer by stackingthe one or more of the fabric sheets on the pre-base layer such that theend portions of the of the respective fabric sheets in thepre-reinforcement layer contact each other in the circumferentialdirection of the mold and discontinuous interfaces of the respectivefabric sheets in the pre-reinforcement layer may be formed at thecontacting end portions of the respective fabric sheets in thepre-reinforcement layer in the axial direction of the mold. Preferably,the discontinuous interfaces formed in the pre-base layer and thediscontinuous interfaces formed in the pre-reinforcement layer may notbe aligned with each other.

In the forming the pre-reinforcement layer, the fabric sheets may bestacked in multiple layers, and the one or more fabric sheets may bestacked. The end portions of the respective fabric sheets in thepre-reinforcement layer may contact each other in the circumferentialdirection of the wheel and the discontinuous interfaces thereof may beformed at the contacting end portions of the respective fabric sheets inthe pre-reinforcement layer in the axial direction of the wheel. Thediscontinuous interfaces in the pre-reinforcement layer may not bealigned with each other.

In the preparing the mold, the prepared mold may have a shapecorresponding to a shape of the rim. The rim may include or be dividedinto a rim body having a cylindrical shape, a rim outer portion, and arim inner portion. The rim outer portion and the rim inner portion maybe formed both axial ends of the rim body so as to have an increaseddiameter. In the preparing the fabric sheets, each fabric sheet mayinclude, or be divided into a body area forming the rim body, an outerarea forming the rim outer portion, and an inner area forming the riminner portion. The outer area and the inner area of the fabric sheet mayinclude cutting portions, which may be cut in the axial direction of themold and may be spaced apart from each other in the circumferentialdirection of the mold.

The cutting portions, formed in the preparing the fabric sheets, may bespaced apart from each other by a length of an arc corresponding to apredetermined angle about a center of the rim, and the predeterminedangle may be equal to or less than about 5 degrees.

In the molding, the resin may be injected and cured into the stackedfabric sheets by resin transfer molding (RTM).

The method may further include preparing a plurality of resin films bymolding a resin to have a film shape. Preferably, in the stacking, thefabric sheets and the resin films may be alternately stacked, and, inthe molding, the fabric sheets and the resin films may be subjected tohot compression molding.

In the preparing the fabric sheets, each fabric sheet may include, or bedivided into a body area forming a rim body, an outer area forming a rimouter portion, and an inner area forming a rim inner portion.Preferably, the outer area and the inner area of the fabric sheet mayinclude cutting portions, which are cut in the axial direction of themold and may be spaced apart from each other in the circumferentialdirection of the mold. Preferably, in the stacking, among resin films,with which the pre-base layer is impregnated, a heat-resistant resinfilm is disposed on the body area of the each of the fabric, animpact-resistant resin film is disposed on the outer area and the innerarea of the each of the fabric sheet, and a fatigue-resistant resin filmis impregnated in the pre-reinforcement layer.

Other aspects of the vehicle are disclosed infra.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a view illustrating a conventional hybrid-type wheel in therelated art;

FIG. 2 is a view illustrating an exemplary method of manufacturing anexemplary composite rim of an exemplary vehicle wheel according to anexemplary embodiment of the present invention;

FIG. 3 is a view illustrating an exemplary composite sheet applied to anexemplary composite rim of an exemplary vehicle wheel according to anexemplary embodiment of the present invention;

FIGS. 4A and 4B are views illustrating an example of stacking exemplarycomposite sheets upon the manufacture of an exemplary composite rim ofan exemplary vehicle wheel according to an exemplary embodiment of thepresent invention; and

FIGS. 5A and 5B are views illustrating an exemplary method ofmanufacturing an exemplary rim of an exemplary vehicle wheel accordingto an exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprise”, “include”, “have”, etc.when used in this specification, specify the presence of statedfeatures, regions, integers, steps, operations, elements and/orcomponents but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components, and/or combinations thereof.

It is understood that the term “vehicle” or “vehicular” or other similarterm as used herein is inclusive of motor vehicles in general such aspassenger automobiles including sports utility vehicles (SUV), buses,trucks, various commercial vehicles, watercraft including a variety ofboats and ships, aircraft, and the like, and includes hybrid vehicles,electric vehicles, plug-in hybrid electric vehicles, hydrogen-poweredvehicles and other alternative fuel vehicles (e.g. fuels derived fromresources other than petroleum). As referred to herein, a hybrid vehicleis a vehicle that has two or more sources of power, for example bothgasoline-powered and electric-powered vehicles.

Further, unless specifically stated or obvious from context, as usedherein, the term “about” is understood as within a range of normaltolerance in the art, for example within 2 standard deviations of themean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%,3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unlessotherwise clear from the context, all numerical values provided hereinare modified by the term “about.”

Hereinafter, an exemplary embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings. Thepresent invention, however, are not limited to the embodiments disclosedhereinafter and may be embodied in many different forms. Rather, theseexemplary embodiments are provided so that this invention will bethrough and complete and will fully convey the scope to those skilled inthe art. In the drawings, the same reference numerals denote the sameelements.

FIG. 1 is a view illustrating a convention hybrid-type wheel, FIG. 2 isa view illustrating an exemplary method of manufacturing an exemplarycomposite rim of an exemplary vehicle wheel according to an exemplaryembodiment of the present invention, FIG. 3 is a view illustrating anexemplary composite sheet applied to the composite rim of an exemplaryvehicle wheel according to v embodiment of the present invention, FIGS.4A and 4B are views illustrating an example of stacking composite sheetsupon the manufacture of an exemplary composite rim of v vehicle wheelaccording to an exemplary embodiment of the present invention, and FIGS.5A and 5B are views illustrating an exemplary method of manufacturing anexemplary rim of v vehicle wheel according to an exemplary embodiment ofthe present invention.

The rim of the vehicle wheel according to the present invention isapplied to a rim of the hybrid-type wheel 10 illustrated in FIG. 1 inwhich the spoke 20 is formed of a metal, such as steel, an aluminumalloy, or a magnesium alloy, and the rim 30 is formed of afiber-reinforced composite, which is reinforced with high-rigidity andhigh-strength continuous fibers, such as carbon fibers, glass fibers, oraramid fibers.

The rim 30 may be a rim of a vehicle wheel, which may be formed bystacking composite sheets 100, which are prepared by impregnatingcontinuous fibers with a resin to form a sheet. The composite sheets 100may be stacked in multiple layers in a manner such that the end portionsthereof may contact each other in the circumferential direction D3 ofthe wheel and such that the discontinuous interfaces thereof, which areformed at the contact regions of the respective composite sheets 100along the axial direction D1 of the wheel, may not be aligned with eachother. By arranging the discontinuous interfaces so as not to be alignedwith each other, a difference in thickness and a difference inmechanical properties, which may locally occur at mutual couplingsurfaces, may be prevented. Here, the composite sheet 100 may beprepared by impregnating a continuous fiber fabric sheet 100,manufactured by weaving continuous fibers, with a resin. As will bedescribed later, the method of impregnating the continuous fiber fabricsheet 100 with the resin may be applied in various ways.

To describe the structure of the rim 30 in detail, the rim 30 mayinclude a base layer 310 in which the respective composite sheets 100may be disposed such that the end portions thereof may contact eachother in the circumferential direction D3 of the wheel and thediscontinuous interfaces thereof may be formed at the contactingregions, i.e. contacting end portions, of the respective compositesheets 100 in the axial direction D1 of the wheel, and a reinforcementlayer 320 in which the composite sheets 100 may be stacked on the baselayer 310 such that the ends thereof contact each other in thecircumferential direction D3 of the wheel and the discontinuousinterfaces thereof may be formed at the contacting regions, i.e.contacting end portions, of the respective composite sheets 100 in theaxial direction D1 of the wheel. Preferably, the discontinuousinterfaces formed in the base layer 310 and the discontinuous interfacesformed in the reinforcement layer 320 may not be aligned with eachother.

In addition, the reinforcement layer 320 may be formed in a singlelayer, but may be formed in multiple layers by stacking the compositesheets 100. Preferably, the composite sheets 100, which are in the samelayer, may be stacked such that the ends thereof may contact each otherin the circumferential direction D3 of the wheel and the discontinuousinterfaces thereof may be formed at the contact regions of therespective composite sheets 100 in the axial direction D1 of the wheel,and that the composite sheets 100, which may be in different layers, maybe stacked such that the discontinuous interfaces thereof may not bealigned with each other.

The discontinuous interfaces described above may provide a consistentthickness and consistent mechanical rigidity and strength of the entirerim despite a difference in thickness between the contact regions of therim 30 or deterioration in or concentration of mechanical rigidity andstrength at the contacting regions.

As illustrated in FIG. 1, the rim 30 may be divided into a rim body 31having a cylindrical shape, and a rim outer portion 32 and a rim innerportion 33, which may be formed by bending both axial ends of the rimbody 31 so as to have an increased diameter.

For example, the rim 30 may have different diameters of respective areasthereof, the present invention provides an improvement in the shape ofthe composite sheets 100 to be stacked for the manufacture of the rim30.

As shown in FIG. 3, the composite sheet 100 may include or be dividedinto a body area 110 forming the rim body 31, an outer area 120 formingthe rim outer portion 32, and an inner area 130 forming the rim innerportion 33. The outer area 120 and the inner area 130 of the compositesheet 100 may be formed with cutting portions 101, which may be cut inthe axial direction D1 of the wheel and may be spaced apart from eachother in the circumferential direction D3 of the wheel. The outer area120 and the inner area 130 may be applied to the rim outer portion 32and the rim inner portion 33 of the rim 30, which have a diametergreater than that of the rim body 31 of the rim 30. In order to stackthe composite sheets 100 on the corresponding portions, the adjacentcomposite sheets 100 may be stacked so as to overlap each other. Whenthe direction in which the continuous fibers of the composite sheet 100are arranged deviates from the axial direction D1 of the wheel by anangle greater than about 10 degrees, however, it is possible to easilystack the composite sheets 100 without the cutting portions 101 due tothe characteristics of a continuous fiber fabric, and therefore, it isnot necessary to form the cutting portions 101 in the composite sheets100. Thus, the criteria for forming the cutting portions 101 in thecomposite sheets 100 may be set to the case in which the direction inwhich the continuous fibers of the composite sheet 100 has an angleequal to or less than about 10 degrees with respect to the axialdirection D1 of the wheel.

The distance between the cutting portions 101, as shown in FIG. 2, maybe set in a manner such that the cutting portions 101 may be spacedapart from each other by the length of an arc corresponding to an angleθ about the center of the rim 30. Thus, the angle θ may be equal to orless than about 5 degrees in consideration of a difference in diameterbetween the rim outer portion 32, the rim inner portion 33 and the rimbody 31.

In the present invention, when the composite sheets 100 may be stackedto form the rim 30, the resin, with which the body area 110 of thecomposite sheet 100, which may form the base layer 310, may beimpregnated, may be a heat-resistant resin. The resin, with which theouter area 120 and the inner area 130 of the composite sheet 100 may beimpregnated, may be an impact-resistant resin. In addition, the resin,with which the reinforcement layer 320 may be impregnated, may be afatigue-resistant resin. In this way, by applying the resin having goodheat resistance to the innermost surface of the rim 30, deterioration inthe mechanical properties of a rim portion close to a brake disc may beprevented and desired mechanical properties of the rim outer portion 32and the rim inner portion 33 may be obtained. For example, theheat-resistant resin may suitably include a multifunctional glycidylamine type epoxy, novolac type epoxy, or mixed epoxy thereof, and theimpact-resistant resin and the fatigue-resistant resin may be a resinthat may be prepared by adding rubber or polyurethane to epoxy havinghigh brittleness so as to improve impact resistance ability anddurability. However, the impact-resistant resin and thefatigue-resistant resin may be a trifunctional or bifunctional resin.

A method of manufacturing the rim configured as described above will bedescribed.

In the method of manufacturing the rim of the vehicle wheel according tothe present invention, first, molds 1, 2 and 3 having shapescorresponding to the shape of the rim 30 may be prepared (moldpreparation step).

At this time, the molds 1, 2 and 3 may be prepared so as to correspondto the shape of the rim 30, which may include or be divided into the rimbody 31 having a cylindrical shape and the rim outer portion 32 and therim inner portion 33, which may be formed by bending both axial ends ofthe rim body 31 so as to have an increased diameter.

Subsequently, a plurality of continuous fiber fabric sheets 100 may beprepared by weaving continuous fibers (continuous fiber fabric sheetpreparation step).

At this time, the continuous fiber fabric sheet 100 may have anisotropicmechanical properties including the in-plane isotropy of the rim 30. Therigidity E₀ of the rim 30 in the circumferential direction D3 may differfrom the axial rigidity E₉₀, and the in-plane shear rigidity Gr of therim 30 may be independent of the rigidity in the circumferentialdirection D3 and the rigidity in the axial direction D1. As such, theweaving and stacking patterns of the continuous fiber fabric sheets 100may be implemented in various ways.

For example, various examples may be made as follows:

Example 1: [±θ], [0/90]

Example 2: [±θ/0/±θ], [+θ/0/−θ], [±θ/90/±θ], [+θ/90/−θ]

Example 3: [±θ/0/90/±θ], [+θ/0/90/−θ]

Unit patterns, such as the weaving and stacking patterns of Example 1 toExample 3 described above, may be repeatedly stacked. The weaving andstacking patterns of the continuous fiber fabric sheets 100 may not belimited to the proposed examples, and may be modified and implemented invarious ways.

In addition, the continuous fiber fabric sheet 100 may have a widthcapable of covering the overall rim width, or may take the form of anarrow strip for local application. For example, in the case of a0-degree unidirectional (UD) fabric, the continuous fiber fabric sheet100 may take the form of a narrow strip since it is necessary to applypieces of fabric having different lengths for each area according tovariation in the diameter in the axial direction D1 of the rim 30.

The continuous fiber fabric sheet 100, as illustrated in FIG. 3, mayinclude or be divided into the body area 110 forming the rim body 31,the outer area 120 forming the rim outer portion 32, and the inner area130 forming the rim inner portion 33. Preferably, the outer area 120 andthe inner area 130 of the continuous fiber fabric sheet 100 may beformed with the cutting portions 101, which may be cut in the axialdirection D1 of the mold and may be spaced apart from each other in thecircumferential direction D3 of the mold.

Then, the continuous fiber fabric sheets 100 may be stacked on theprepared mold (stacking step). In the stacking step, the continuousfiber fabric sheets 100 may be stacked in multiple layers on theprepared mold such that the ends thereof may contact each other in thecircumferential direction of the mold and such that the discontinuousinterfaces thereof, which may be formed at the contact regions of therespective composite sheets 100 along the axial direction of the mold,may not be aligned with each other.

At this time, the stacking step may include a pre-base layer formingprocess of forming a pre-base layer 310 in which the continuous fiberfabric sheets 100 may be disposed on the prepared mold such that theends thereof may contact each other in the circumferential direction D3of the mold and such that the discontinuous interfaces thereof may beformed at the contact regions of the respective c continuous fiberfabric sheets 100 in the axial direction D1 of the mold and apre-reinforcement layer forming process of forming a pre-reinforcementlayer 320 in which the continuous fiber fabric sheets 100 may be stackedon the pre-base layer 310 such that the ends thereof may contact eachother in the circumferential direction of the mold and such that thediscontinuous interfaces thereof may be formed at the contacting regionsof the respective continuous fiber fabric sheets 100 in the axialdirection of the mold so as not to be aligned with the discontinuousinterfaces formed in the pre-base layer 310.

In addition, in the pre-reinforcement layer forming process, thecontinuous fiber fabric sheets 100 may be stacked in multiple layers ina manner such that the ends of the continuous fiber fabric sheets 100 inthe same layer may contact each other in the circumferential directionD3 of the mold and the discontinuous interfaces thereof may be formed atthe contact regions of the respective continuous fiber fabric sheets 100in the axial direction D1 of the mold and such that the discontinuousinterfaces formed by the continuous fiber fabric sheets 100 in differentlayers may not be aligned with each other.

The arrangement and stacking of the continuous fiber fabric sheets 100may be applied in various ways so long as the discontinuous interfacesof the respective continuous fiber fabric sheets 100 may not be alignedwith each other.

For example, as illustrated in FIGS. 4A and 4B, when the pre-base layer310 and the pre-reinforcement layer 320 may be formed, the discontinuousinterfaces {circumflex over (1)}, {circumflex over (2)}, {circumflexover (3)}, {circumflex over (4)}, {circumflex over (5)} and {circumflexover (6)} formed in different layers may be disposed so as not to bealigned with each other. Here, the discontinuous interfaces {circumflexover (1)}, {circumflex over (2)}, {circumflex over (3)}, {circumflexover (4)}, {circumflex over (5)} and {circumflex over (6)} may bedisposed in a regular pattern, as illustrated in FIG. 4A, or may bedisposed in an irregular pattern, as illustrated in FIG. 4B.

After the continuous fiber fabric sheets 100 are stacked, a resin may beinjected and cured into the stacked continuous fiber fabric sheets 100(molding step).

The molding step may be implemented in various ways.

For example, a resin may be injected and cured into the stackedcontinuous fiber fabric sheets 100 by a resin transfer molding (RTM)method.

In addition, as illustrated in FIGS. 5A and 5B, after preparing aplurality of resin films 200 by molding a resin to have a film form(resin film preparation step), the continuous fiber fabric sheets 100and the resin films 200 may be alternately stacked in the stacking step,and the fabric sheets 100 and the resin films 200 may be subjected tohot compression molding using the molds 2 and 3 to manufacture a moldedarticle 300 in the molding step.

When the resin films 200 are applied as described above, among the resinfilms 200, with which the pre-base layer 310 is impregnated, the resinfilm 210 disposed on the body area of the continuous fiber fabric sheet100 may be a heat-resistant resin film, and the resin film 220 disposedon the outer area and the inner area of the continuous fiber fabricsheet 100 may be an impact-resistant resin film. In addition, the resinfilm 230, with which the pre-reinforcement layer 320 is impregnated, maybe a fatigue-resistant resin film.

As the resin is injected and cured into the stacked continuous fiberfabric sheets 100 by a resin transfer molding (RTM) method, therespective areas of the continuous fiber fabric sheet 100 may beimpregnated with the heat-resistant resin, the impact-resistant resin,and the fatigue-resistant resin so as to provide a rim that includesdifferent types of resins for each area.

In the present invention, for the clarity of description, the state inwhich the continuous fiber fabric sheet 100 is impregnated with a resinhas been designated and described as a composite sheet. Thus, thecontinuous fiber fabric sheet and the composite sheet are denoted by thesame reference numeral 100. In addition, the pre-base layer formed ofthe continuous fiber fabric sheet and the base layer formed of thecomposite sheet are denoted by the same reference numeral 310, and thepre-reinforcement layer formed of the continuous fiber fabric sheet andthe reinforcement layer formed of the composite sheet are denoted by thesame reference numeral 320.

In various exemplary embodiments of the present invention, adiscontinuous fabric may be formed using continuous fibers, and aplurality of layers of fabric may be stacked so as to contact each otherin the circumferential direction of a wheel, such that a rim of avehicle wheel capable of satisfying reduced weight, high mechanicalrigidity, and high strength through the use of continuous fibers may bemanufactured.

In addition, the layers of discontinuous fabric may contact each othersuch that discontinuous interfaces thereof are not aligned with eachother, such that it is possible to prevent a problem of the related artin which a rim is manufactured by stacking layers of discontinuousfabric so that ends thereof overlap each other, thus having difficultyin realizing consistent mechanical strength and rigidity for each area.

In addition, by applying a resin having good heat resistance to theinnermost surface of the rim to which heat generated in a brake disc istransferred, deterioration in the mechanical properties of a rim portionthat is close to the brake disc may be prevented.

Although the various exemplary embodiments of the present invention havebeen described above with reference to the accompanying drawings, thoseskilled in the art will appreciate that the present invention can beimplemented in various other embodiments without changing the technicalideas or features thereof.

What is claimed is:
 1. A rim of a vehicle wheel, comprising: a pluralityof composite sheets, each of which comprises a fabric sheet and a resin,where the resin is impregnated in the fabric sheet, wherein each of thefabric sheet comprises: continuous fibers; a base layer comprising oneor more of the composite sheets wherein end portions of the respectivecomposite sheets in the base layer contact each other in thecircumferential direction of the wheel and discontinuous interfaces ofthe respective composite sheets in the base layer are formed at thecontacting end portions of the respective composite sheets in the baselayer in the axial direction of the wheel; and a reinforcement layerdisposed on the base layer and comprising one or more of the compositesheets wherein end portions of the respective composite sheets in thereinforcement layer contact each other in the circumferential directionof the wheel and discontinuous interfaces of the respective compositesheets in the reinforcement layer are formed at the contacting endportions of the respective composite sheets in the reinforcement layerin the axial direction of the wheel, wherein the reinforcement layer isformed in multiple layers by stacking the one or more composite sheets,and the discontinuous interfaces of the respective composite sheets inthe reinforcement layer are not aligned with each other, and wherein thediscontinuous interfaces formed in the base layer and the discontinuousinterfaces formed in the reinforcement layer are not aligned with eachother.
 2. The rim according to claim 1, comprising: a rim body having acylindrical shape; a rim outer portion; and a rim inner portion, whereinthe rim outer portion and the rim inner portion are formed both axialends of the rim body so as to have an increased diameter.
 3. The rimaccording to claim 2, wherein each of the composite sheets comprises abody area forming the rim body, an outer area forming the rim outerportion, and an inner area forming the rim inner portion, and whereinthe outer area and the inner area of the composite sheet comprisescutting portions, which are cut in the axial direction of the wheel andare spaced apart from each other in the circumferential direction of thewheel.
 4. The rim according to claim 3, wherein the cutting portions arespaced apart from each other by a length of an arc corresponding to apredetermined angle about a center of the rim, and the predeterminedangle is equal to or less than about 5 degrees.
 5. The rim according toclaim 1, wherein each of the composite sheets comprises a body areaforming the rim body, an outer area forming the rim outer portion, andan inner area forming the rim inner portion, and wherein the outer areaand the inner area of the composite sheet comprises cutting portions,which are cut in the axial direction of the wheel and are spaced apartfrom each other in the circumferential direction of the wheel.
 6. Therim according to claim 5, wherein a heat-resistant resin is impregnatedin the body area of the one or more composite sheets constituting thebase layer, wherein an impact-resistant resin is impregnated in theouter area and the inner area of the one or more composite sheetsconstituting the base layer, and wherein a fatigue-resistant resin isimpregnated in the one or more of the composite sheets constituting thereinforcement layer.
 7. A vehicle comprising a rim according to claim 1.8. A method of manufacturing the rim of a vehicle wheel, the rimaccording to claim 1.